Why does the Red Hat Network Registration Client return the error “No Route to Host”?
The system you are running the Red Hat Network Registration Client (rhn_register) on is not connected to the Internet, or the system is attempting to access Red Hat Network through a proxy server. Proxy server settings can be configured in the newest version of rhn_register available at http://www.redhat.com/support/errata/RHBA-2000-138.html. For instructions on configuring the proxy server, refer to the section called Configuring the Red Hat Network Registration Client in Chapter 2.